Latency Analyses of CC-NUMA and CC-COMA Rings

This paper focuses comparative performance modeling and evaluation of CC-NUMA and CC-COMA on a hierarchical ring shared-memory architecture. Intensive performance measurements of the two models have been conducted on the KSR-1. The experimental results support the analytical models, and present practical observations and comparisons of the two cache coherence memory systems. Our analytical and experimental results show that a CC-COMA system balances the work load well. However the overhead of frequent data movement may match the gains obtained from improving load balance. Although a CC-NUMA system may not automatically balance the load at the system level, it provides an option for a user to explicitly handle data locality for a possible performance improvement.